Nickel Complexes Bearing ONS Chelating Ligands: A Promising Contender for In Vitro Cytotoxicity Effects on Human Pancreatic Cancer MIA-PaCa‑2 Cells

The highly chronic human pancreatic cancer cell is one
of the major
reasons for cancerous death. Nickel complexes are recently gaining
interest in anticancer activities on different types of cancer cells.
Hence, in this study, we synthesized and characterized a series of
ONS donor ligands [2-HO–C6H4–CHN–(C6H4)–SH] (L1), [2-OH-3-OMe–C6H3–CHN–(C6H4)–SH] (L2), [2-OH-3,5-(C(Me)3)2–C6H2–CHN–(C6H4)–SH] (L3), [2-OH–C6H4–CHN–(C6H4)–SMe] (L4), [2-OH-3-OMe–C6H3–CHN–(C6H4)–SMe] (L5), [2-OH-3,5-(C(Me)3)2–C6H2–CHN–(C6H4)–SMe] (L6) and their Ni(II)
metal complexes [(MeOH)Ni(L1–L1–4H)] (1), [(MeOH)Ni(L2–L2–4H)] (2), [(MeOH)Ni(L3–L3–4H)] (3), [(L4–H)2Ni] (4), [(L5–H)2Ni] (5), and
[(L6–H)2Ni] (6). The single-crystal
X-ray diffraction data of complexes 1 and 4 were collected to elucidate the geometry around the metal center.
The anticancer activity of complexes 1–6 was investigated
on human pancreatic cancer cell line MIA-PaCa-2, which revealed that
complexes 4 and 6 were the most significantly
effective in decreasing the cell viability of cancer cells at the
lowest dose. The structure parameters obtained from single-crystal
X-ray diffraction data are found to be in good agreement with the
data from density functional theory and Hirshfeld surface analysis
for complex 1.